The universe really threw us a curve,” Kogut said. “Instead of the faint signal we hoped to find, here was this booming noise six times louder than anyone had predicted.”
Detailed analysis of the signal ruled out primordial stars or any known radio sources, including gas in the outermost halo of our own galaxy.
Other radio galaxies also can’t account for the noise – there just aren’t enough of them.
“You’d have to pack them into the universe like sardines,” said study team member Dale Fixsen of the University of Maryland. “There wouldn’t be any space left between one galaxy and the next.”
The signal is measured to be six times brighter than the combined emission of all known radio sources in the universe.
For now, the origin of the signal remains a mystery.
“We really don’t know what it is,”said team member Michael Seiffert of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
And not only has it presented astronomers with a new puzzle, it is obscuring the sought-for signal from the earliest stars. But the cosmic static may itself provide important clues to the development of galaxies when the universe was much younger, less than half its present age. Because the radio waves come from far away, traveling at the speed of light, they therefore represent an earlier time in the universe.
“This is what makes science so exciting,” Seiffert said. “You start out on a path to measure something – in this case, the heat from the very first stars – but run into something else entirely, some unexplained.”
http://www.space.com/scienceastronomy/090107-aas-loud-cosmic-noise.html